(1) Field of the Invention
The present invention relates to an improved firestop assembly for use in buildings which allows penetration of flammable piping through a floor made of sheet material, particularly those made of wood, without creating a firepath through the floor. In particular, the present invention relates to a fitting which includes a plug means for closing the piping. The plug means is activated by heat to seal off a section of the coupling when fire penetrates the pipe in a lower story of a building. The assembly prevents the spread of fire through piping mounted between upper and lower stories in the building. The assembly can be connected to a tee pipe mounted in the joist space defined by the floor joists between the floor and a ceiling in the building. The tee pipe, if non-flammable, helps to prevent the spread of fire through the crawl space and provides a horizontal extension for connection to a water operated fixture or the like.
(2) Prior Art
Flammable pipe penetrations through floors in multi-story buildings create a number of problems because a seal between the floors is broken by the pipe. When fire burns through the pipe in a lower story, the fire and smoke can penetrate an upper story because the pipe functions as a chimney. The problem of fire safety when flammable piping penetrates fire rated floors is particularly troublesome, since these openings can jeopardize the fire integrity of the entire building. As a result, in most buildings, plastic (PVC) pipe is not used for these penetrations, since fire can easily penetrate through the floor by burning the pipe. Therefore, a primary problem has been to develop a device which solves the fire safety problem associated with pipe penetrations so that plastic pipe can be used in buildings.
My U.S. Pat. Nos. 4,583,565, 4,638,829 and 4,724,858 show the prior art. U.S. Pat. No. 4,583,565 and 4,638,829 describe firestop fittings with a main conduit and an integral extension conduit mounting a fire releasable plug means made of cast iron or some other non-flammable material. This combination works very well. U.S. Pat. No. 4,724,858 shows a firestop stack fitting for concrete floors wherein the main conduit and the extension conduit are composed of a flammable material connected to a flammable coupling mounted through the concrete floor. A non-flammable sleeve is mounted inside of the main conduit and helps to prevent the spread of fire by sealing off the inside of the main conduit from oxygen. This construction is less expensive and is preferred. There is, however, a need for a firestop stack fitting that helps retard fire and smoke from penetrating through a pipe penetration between stories of a building where the floor and ceiling are made of sheet material supported by floor joists.